Gasoline composition



United States GASOLINE COMPOSITION No Drawing. Application May 5, 1955 Serial No. 506,382

14 Claims. (CI. 44-59) The present invention is concerned with improved petroleum fuels, particularly gasolines and more par ticularly aviation gasolines and with rust-inhibiting compositions of said gasolines. The invention is further concerned with aviation gasolines that are dyed for the purpose of identification and that are provided with minor proportions of, a rust-inhibiting additive. The invention especially relates to dyed aviation gasolines that contain rust-inhibiting additives in the form of mixed ammonium saltsof hydrocarbon sulfonic acids and alkyl phosphoric acids. With respect to these aviation gasolines containing said rust-inhibiting additives, the invention pertains further" to means for stablizing the dyed color of such gasolines by incorporating in the rust-inhibiting composition a very minor proportion of ethylene diamine.

The compositions-and characteristics of aviation gasolines are well-known in the art and are set forth, for example, in United States military specification MILF 5572-1 and in ASTM specification D9l050T. In these publications it will be observed .that aviation gasolines are generally available in three or four grades, depending upon their anti-knock values. The three grades containing up to 4.,6 cc. of tetraethyl lead per gallon are referred to as grade 91-98, grade 100-130 and grade 115-145. All of these fuels have vapor pressures below 7 lbs/sq. in. at 100 F. and boil below about 338 F. They have at least 50% distilled at 221 F. by ASTM method D86 and generally comprise mixtures of aromatic hydrocarbons, in no more than 20% concentration by volume, with selected saturated hydrocarbons, principally aliphatic. These fuels are particularly marked by the fact that they atent O are substantially free of olefinic hydrocarbons, which are intentionally excluded primarily because it is necessary that the fuels have excellent storage stability characteristics. Olefinic hydrocarbons, tending to be somewhat unstable in storage, are excluded from these fuels; and the fuels are therefore characterized by a very high degree of chemical stability, particularly with respect to their freedom from tendency to form peroxides and gum. Their gum content, even after severe oxidation at 212 F. with oxygen at 100 lbs/sq. in. for a period of sixteen hours, is less than 6 mgs. per 100 cc.

It may further be observed in the ASTM specifications for aviation gasoline that each one of the gasoline grades may be identified by a'particular type of colored dye. Thus, the grade 91-98 fuel is colored blue by the use of a dye that must be selected from certain alkyl amino or aryl amino derivatives of anthraquinone. The grade 100-130 and 115-145 fuels are similarly colored green and purple, respectively, by the addition of other particular dyes or, combinations of dyes.

Inasmuch as the ASTM and military specifications concerning gasoline dyes are so stringently set forth, it follows that it is extremely important to maintain or stabilize the color that a dye imparts to a gasoline. It would be undesirable to have the color fade during storage; and it wouldbe particularly undesirable to have the dye change color so markedly as to cause confusion as to the grade of the gasoline. It would further be undesirable to incorporate an additive within a dyed gasoline which would have the eifcct of discoloring or changing the color of the gasoline to any marked extent.

Recently, with respect to aviation gasolines as well as other petroleum products, rust-inhibiting additives that are adapted to inhibit the corrosion of metal surfaces with which the products come in contact have appeared desirable. It has been a particular objective to prevent or reduce the corrosion that has been found to occur 'in pipe lines, storage tanks, oil cargo vessels, etc.

To date, a number of additives have been incorporated within aviation gasolines and other petroleum products in an effort to solve the above corrosion problem. Watersoluble rust inhibitors have been suggested because the corrosion is usually associated with the presence of water; but inhibitors of this type are not particularly desirable since they are largely lost when water is separated from the oil products during handling operations. Furthermore, the water-soluble inhibitors are necessarily 'introduced to the oil products in the form of aqueous solutions, and the addition of the water in the form of these solutions merely aggravates the problem which the inhibitor is intendedto solve.

Inhibiting compositions which have been demonstrated to be markedly eifective in combating the above corrosion problem are described at length in two recent patent applications, S. N. 325,694, filed December '12; 1952,"now

U. Patent No. 2,791,495, and S. N. 358,178, filed May 28, 1953, now U. S. Patent No. 2,819,954. These compositions in general are hydrocarbon-soluble mixtures of ammonium salts of sulfonic acids and ammonium salts of sulfonic acids and ammonium salts of alkyl phosphoric acids. Mixtures of these two classes of compounds have been found to demonstrate very desirable synergistic eifects with respect to their rust-preventive qualities.

Ammonium sulfonates that may be used in the abovementioned rust-inhibiting compositions include ammonium mahogany sulfonates which are derived from the neutralization with ammonia of mahogany sulfonic acids. These acids are the oil-soluble petroleum sulfonic acids which in turn are derived in the course of white oil production when sulfuric acid is used to treat a petroleum hydrocarbon oil. Mahogany acids are generally characterized by molecular weights of about 350 to 650.

Other sulfonic acids that are suitable for use in the above rust-inhibiting compositions include the alkyl aryl sulfonic acids such as the sulfonic acids of polyalkyl benzene, wax-alkylated toluene or parafiin wax itself. A particularly preferred type of ammonium sulfonate, however, is the ammonium sulfonate of benzene which has been alkylated with a propylene polymer. The poly propylene substituent of the sulfonate preferably contains about 9-18 carbon atoms in its chain and preferably about 12 carbon atoms. Furthermore, between one and three such chains of polypropylene, may be substituted into the aromatic nucleus. Thus, a particularly preferred ammonium sulfonate is ammonium-didodecyl benzene sulfonate. The manner of preparing this sulfonate as well as the other sulfonates mentioned above is wellknown to those skilled in the art and a detailed discussion of this information is not included in the present descrip tion.

Ammonium organo-phosphates that are suitable constituents for use in the above-described rust-inhibiting compositions include the ammonium salts of organic phosphoric acids wherein the organic radical may be normal, branched or alicyclic in structure. In general, the phosphates are prepared by reacting ammonia with an appropriate alkyl phosphoric acid. The alkyl phosphoric acids in turn are conveniently prepared by -react ing an oxide of phosphorus, preferably P 0 with an I A t aliphaticalcohol. Preferred alcohols for this purpose are the monohydric primary alcohols having 6-18 carbon atoms. Depending upon the reaction proportions and the reaction conditions, monoor di-alkyl phosphoric acids may be obtained. It is not considered, feasible to make the. neutral tri-alkyl phosphate from an alcohol with P Accordingly, this. constituent of the rustinhibiting composition may be. best defined as the ammonium salt of the-reaction product of P 0 and an alcohol or alternatively, as the ammonium salt of mixed alkyl phosphoric. acids.

Particularly preferred ammonium alkyl phosphate salts are those wherein the alkyl: components are derived by the oxonation and subsequent hydrogenation of olefins and olefinic polymers and. copolymers. Thus, an especially preferred. ammonium alkyl phosphate is the ammonium salt of, di-isooctyl. phosphoric acid wherein the isooctyl alcohol employed in the preparation of the alkyl phosphoric acid is derived from the oxonation. and hydrogenation of a-.C copolymer of propylene and butene. The copolymer itself is in' reality a mixture of isomers, and the alcohol derived from the copolymer is popularly known as C Oxo alcohol.

The composition and structure of the C Oxo-alcohol obtained from a mixture of C olefins of the type described above and more specifically of C olefins derived from a refinery gas stream containing propylene and mixed normal and iso-butylenes are now well understood. This- Oxo-alcohol has the following general analysis:

Oxo-alcohols of higher molecular weight are believed to have compositions generally analogous to that specified above, chain lengths and degree of branching depending on the type of olefins, used. It is noted in this respect that even when pure straight-chain olefins are used as the starting materials, the alcohols obtained contain large amounts of branched-chain compounds. Although the composition of these higher Oxo-alcohols is too complicated to permit a complete analysis of all their components, it has been found by infra-red absorption spectrum analysis that C Oxo-al.cohol, for example, has the averagestructural. composition of tetramethyl nonanol and is free of quaternary carbon atoms.

Specific examples. of still other organic phosphoric acid esters which may be converted to ammonium salts and employed in the invention are dicyclohexyl phosphoric 4. acid, hexyl lauryl phosphoric acid, dicapryl phosphoric acid, caprylcaprylyl phosphoric acid, etc

The rust-inhibiting compositions described above may be prepared by first forming the ammonium salts of the various acids and thereafter combining or admixing the two types of salts. Preferably, the acids are first mixed together and thereafter neutralized by treatment with ammonia. Furthermore, the compositions may be incorporated directly within the aviation gasoline; or they may be added in the form of a concentrate. Suitable concentrates, for example, may be prepared by dissolving the compositions in alcoholic solutions or in hydrocarbon diluents such as toluene, kerosine, heating oil or other middle distillate fractions.

While the above described rust inhibiting compositions have proven very effective as such in aviation gasolines, it has been found that they occasionally cause a fading or change in color of some of the dyes that are used in the gasoline. For example, it has been observed in the case of the grade -130 aviation gasoline that the dye tends to takeon a purple tint when the above compositions are incorporated within the gasoline. Applicable specifications as mentioned heretofore require that this grade of gasoline be dyed green by the incorporation therein of not more than 0.470 gram of a blue dye consisting essentially of 1,4-dialkyl amino anthraquinone and not more than 0.701 gram of a yellow dye consisting essentially of p-dimethyl aminoazobenzene per 100 U. S. gallons of gasoline. The change in color referred to above is undesirable because of the possibility of confusing grade 100-130 gasoline with grade -145, which the specifications require be dyed purple.

It should be noted at this point that the color change in the grade 100-130 gasoline is in no way associated with or accompanied by any change in the characteristics of the gasoline itself. The gasoline has not been observed to suffer either a loss in its octane quality or any depreciation in its stability or other physical quality or chemical characteristic. Accordingly, the phenomenon is apparently associated solely with the dye itself and the rust-inhibiting composition. The nature of this phenomenon is not known, but it has been found that its occurrence can be avoided through the addition of a very minor proportion of ethylene diamine. Specifically, it has been found that the addition of about 0.6 to 4.5 wt. percent ethylene diamine based on the active ingredient of the rust-inhibiting composition is markedly effective in avoiding the occurrence of any color change. With respect to the overall additive composition, it is desirable to incorporate about 1 to 15 lbs. of additive on an active ingredient basis per 1000 bbls. of gasoline within a gasoline in order to realize the rust-inhibiting qualities of the additive. In practice, the amount of additive required will vary somewhat depending on such factors as the relative tendency of the original gasoline to cause rusting, the type of equipment and length of pipeline through which the gasoline is pumped, the type of storage conditions and so forth. In general, additive concentrations of about 2 to 4 pounds of active ingredient per 1000 barrels of gasoline are preferred. A barrel of gasoline weighs about 275 lbs. and the preferred concentrations are therefore about 0.001% by wt. of active rust inhibitor and about 0.000031% of alkylene diamine.

Further relative to the amount of rust-inhibiting composition that it is desired to incorporate within a gasoline, it is necessary to utilize about 1-3 parts of the ammonium alkyl phosphate per part of ammonium sulfonate by weight in order to attain a desirable synergistic coaction between these two materials. A ratio of about one part of the phosphate salt per part of sulfonate salt is especially preferred.

In order to demonstrate the utility and benefits of this invention, the following examples are presented. In

these examples a rusting test was employed which generally corresponds to ASTM test procedure D-665. The

turbine oils, at 140 F., but the temperature is lowered for evaluation of gasolines.

Each of the gasoline samples in the examples was furthermore evaluated as to its color stability by a procedure in which 75 cc. of gasoline is placed in a stoppered 4-oz. bottle and stored in a dark place. The color of the gasoline'is determined periodically by observation.

The gasoline used in the examples had 100 aviation octane number and contained about 4 cc. tetraethyl lead in the form of ethyl aviation fluid per gallon. The dyed color of the gasoline was blue green. The dye was pres ent in a concentration of about 1 gram per 100 gallons of gasoline and consisted of a mixture of 1,4-diisopropyl amino anthraquinone and. para-dimethyl aminoazobenzene. The gasoline had about 625 API gravity, about 6.5 lbs. per sq. in. Reid vapor pressure, an initial boiling point about 100. F., a mid-boiling point about 200 F. and a finalboiling point about 325 F. by ASTM method D-86. Its gum content at time of test was about 1 mg. per 100 cc.

without additives were examined for their color and rust ing characteristics as described above. The additives included rust-inhibiting compositions of the types described in S. N. 325,694 and 358,178 mentioned hereinbefore Table 1 gasoline when this gasoline was provided a rust-inhibiting composition of a type described hereinbefore. It is therefore evident that not all amines nor even all alkyle'ne diamines are suitable for this purpose.

EXAMPLE 2 Inhibitor Concentra- Composition of Inhibitor tion Rust Test Demerit 1 lbs/1,000

bbls.

None 6.9 (Light rust over 1001 0 of area of test ro 1.0 (no rust). 1.0 (no rust);

4.0 (Rust on approx.

% of area of test rod) 100% Additive E 95% Aidlditive E+5% Ethylene diam e. 100% Ethylene diamine 1 Same as footnote 1, Table 1 3 Same as footnote 2, Table 1.

It will be noted in Table 2 that both the non-aminetreated rust inhibitor and the ethylene diamine treated composition give complete protection against rusting of the steel test rod. On the other hand, the uninhibited EFFECT OF PRODUCT SOLUBLE RUST INHIBITORS ON GASOLINE COLOR [Gasoline used: 100/130 aviation gasoline] Inhibitor Gasoline Oolor Aiter Storage 8 Composition of Inhibitor Concentration, lbs./

1,000 Nil} 0 Days 5 Days 9 Days 30 Days No Blue greenno change no change no chan e.

AdditiveE u 5 -do Si. purple cast.-. Si. purple cast Browgnis purple cas 99 Wt. percent Additive E+1 Wt. per- 5 d0 no change no change no change.

cent Ethylene diamine. 98 Wt. percent Additive E+2 Wt per- 5 do rin do Do.

cent Ethylene diamine. 95 Wt. percent Additive E+5 Wt. per- 5 .do Green Trace yellow cast--- Yellow cast.

cent Piperidine. 95 Wt. ercent Additive E+5 Wt. per- 5 do -do do Do.

cent iethylamine. 95 Wt. percent Additive E+5 wt. per- 5 do rio (in D cent Diisopropylarnine.

1 Active ingredient: Concentration of additive in lbs. used to inhibit 1000 bbls. (42 gallons each) of gasoline. 2 1/1 Wt. ratio ammonium di-Cr 0x0 phosphate and ammonium didodecyl benzene sulionate, active ingredient in kerosine.

3 In stoppered 4 oz. bottles in the dark.

It may be seen from the above table that the ethylene diamine-treated rust inhibitor composition is markedly and uniquely eiiective in stabilizing the color of grade 100/ 130 aviation gasoline which contains about 5 pounds active ingredient of a rust-inhibiting composition per 1000 bbls. of gasoline. It will further be seen that gasolines containing the ethylene diamine-rust inhibitor composition experience a color stability which is equivalent to that of the gasoline without any rust inhibitor composition. Other amines such as piperidine, diethyl amine and diisopropyl amine are very materially inferior to ethylene diamine as a treating agent for the rust inhibitor in maintaining the color of a gasoline. In this connection, it will further be noted that a number of other amines including propylene diamine, ethanol amine and di-2- ethyl hexyl amine were also tested and found to be ineffective in stabilizing the color of grade 100/130 aviation gasoline alone or the gasoline containing only the ethylene diamine are unsatisfactory, since rusting of the rod occurs with such fuels. It was further observed that on addition of ethylene diamine without the rust inhibitor to the gasoline, the fuel becomes slightly cloudy and although the ethylene diamine treated gasoline maintains the desired green color without change, there forms a light sediment on storage of the gasoline at the concentration tested. Thus, ethylene diamine alone, while providing color stability, does not provide rust protection and introduces undesirable sedimentation. It is obvious, therefore, that the most satisfactory composition to achieve the desired qualities is the ethylene diamine treated rust inhibitor.

It will be noted that a number of variations and modifications of the invention may be practised without departing from the scope of the invention. Thus, it is contemplated that the present fuel compositions may be =utilizedin automotive engines 'as'well as in aviation enj scavenging agents and the like may be used. It is further contemplated ammonium salts of alkyl substituted 'thiophosphoric acids may on occasion be used to advantage in conjunc'tion with or in place of the ammonium alkyl phosphates mentioned 'here'inbe fore.

What is claimed is:

1. An improved aviation gasoline fuel composition comprising :a major proportion of a stable dyed gasoline, said dye being a mixture of 1,4-dialkyl amino anthraquinone and paradimethyl aminoazobenzene, a minor proportion of a rust inhibitor suflicient to prevent the rusting of metals that come in contact with said fuel composition, *said rust inhibitor consisting of mixed hydrocarbon-soluble ammonium salts of a hydrocarbon sulfonic acid and an alkyl phosphoric acid in a-ratio of about 1:3 to 1:1 by weight, and a minor but color-stabilizing proportion of ethylene diamine.

2. A composition as defined in claim l in which the ammonium sulfonate is ammonium petroleum s'ulfonate.

3. A composition as defined in claim '1 in which the sulf'onate is an ammonium salt of an alkyl aryl sulfonic acid.

4. A composition as defined in claim 1 in which the sulfonate is the ammonium salt of a polypropylene alkylated benzene sulfonic acid, said polypropylene portion having from 9-18 carbon atoms.

5. A composition as defined in "claim 1 in which the sulfonate is didodecyl benzene sulfonate.

6. A composition as defined in claim 1 in which the phosphate is derivedfrom reacting a monohydric aliphatic alcohol containing 6-18 carbon atoms with an oxide phosphorus.

7. A composition as defined in claim '6 in which the alcohol is a mixture of alcohols derived from the oXonation and subsequent hydrogenation of the C copolymer of propylene and butene.

8. An improved aviation gasoline composition comprising a major proportion of substantially stable dyed aviation gasoline, said dye being a mixture of 1,4- dialkyl amino anthraquinone and paradimethyl aminoazobenzene, and about 1 to 15 lbs. of a rust inhibiting and color stabilizing additive per 1000 gallons of .gasoline, said 'additiveconsi'stin g "o'f enryleire diamine and a hydrocarbon-soluble mixture of ammonium salts" 6f alkyl substituted phosphoric acid andfnymb'arbbn sulfonic acid, said additive containing about 1 to'3p'ai't's of said ammonium phosphate per part of said ammonium sulfonate by weight and about 0.6 to 4.5m. percentor said ethylene fdiamine.

9. A composition as defined in claim '8 in which the ratio of the ammonium phosphate tothe ammonium sulfonate is about 1/ 1.

10. A composition as defined in claim 8 in which the gasoline composition contains about 2 to 4 lbs. of the additive per 1000 gallons of gasoline.

11. An improved aviation gasoline fuel composition comprising a major portion of substantially stable dyed gasoline, said dye being a mixture of 1,4-dialkyl amino anthraquinone and par'adimethyl aminoazob'en'zene, and

about 1-15 lbs. of artist-inhibiting and color-stabilizing additive per 1,000 gallons of gasoline, said additive consisting of ethylene diamine and afrniXLu're of ammonium di-isoo'ctyl phosphate and ammonium 'didodec'yl b'enZene sulfonate in a ratio of 1:1 by weight'and about 0.6 to 4.5

weight percent of said ethylene diamine.

12. An improved rust inhibitor for use in dyed aviation gasoline's containing 1,4dialkyl amino anthraquinon'e an'd pa'ra-dimethyl aminoaz'obenzene dyes which comprises about 1 part of a hydrocarbon-soluble ammonium salt of a hydrocarbon sulfonic acid, from about 1 to 3 parts of a hydrocarbon-soluble ammonium salt of an alkyl substituted phosphoric acid, and from about 0.6 to 4.5% by weight, based upon said ammonium salts, of ethylene diamine. k

13. An inhibitor as defined b'y claim 12 wherein said sulfonic acid is didodecyl benzene 'sulfonic acid and said phosphoric acid is a C Ono-substituted phosphoric acid.

14. An inhibitor as defined by claim 13 containing equal .parts of said sulfonic acid salt and said phosphoric acid salt.

' References Cited in the file of this patent UNITED STATES PATENTS 1,992,014 Rogers et al. Feb. 19, 1935 2,080,299 Benning et a1 May 11, 1937 2,447,615 Jones u Aug. 24, 1948 2,512,297 Biswell et a1 June 20, 1950 2,650,198 Kroning et al. Aug. 25, 1953 

1. AN IMPROVED AVIATION GASOLINE FUEL COMPOSITION COMPRISING A MAJOR PROPORTION OF A STABLE DYED GASOLINE, SAID DYE BEING A MIXTURE OF 1,4-DIALKYL AMINO ANTHRAQUINONE AND PARADIMETHYL AMINOAZOBENZENE, A MINOR PROPORTION OF A RUST INHIBITOR SUFFICIENT TO PREVENT THE RUSTING OF METALS THAT COME IN CONTACT WITH SAID FUEL COMPOSITION, SAID RUST INHIBITOR CONSISTING OF MIXED HYDROCARBON-SOLUBLE AMMONIUM SALTS OF A HYDROCARBON SULFONIC ACID AND AN ALKYL PHOSPHORIC ACID IN A RATIO OF ABOUT 1:3 TO 1:1 BY WEIGHT, AND A MINOR BUT COLOR-STABLIZING PROPORTION OF ETHYLENE DIAMINE. 